690 / 2019-05-01 12:09:04

An auxin signaling repressor IAAY contributes to seed germination through down-regulation of ABI3 transcription under salt / drought stress in Arabidopsis

ABI3,Aux/IAA,NaCl,Mannitol,Seed germination

Plant Hormones > Plant Hormones

Seed germination is strictly controlled by phytohormones including gibberellins (GAs) and abscisic acid (ABA) that promotes and inhibit seed germination, respectively. Crosstalk among phytohormones is important to investigate the unknown mechanism underlying in seed germination. The role of auxin in plant growth and development is studied extensively although its role in seed germination is not yet fully understood. Here, we characterized a previously unknown function IAAY in seed germination under NaCl and mannitol stress condition. We show that disruption of IAAY (iaaY-1) delayed seed germination when compared with seeds of Col-0 and transgenic plants overexpressing IAAY in stress condition. Furthermore, under stress condition the IAAY protein was dramatically accumulated during seed germination. Double transgenic plants harboring DR5:: GUS/IAAY were analyzed to investigate the effect of IAAY accumulation on auxin signaling. The accumulated IAAY was found to inhibit auxin signaling during seed germination in stress condition. We also provide the evidence that IAAY down-regulate ABSCISIC ACID INSENSITIVE 3 (ABI3) transcriptions, thereby promoting seed germination. Altogether, our result demonstrate that inhibition of auxin signaling via IAAY contribute to seed germination by down-regulating ABI3 transcription in Arabidopsis.